Study On The Application Of Macro Omnidirectional Light Source To Develop Common Latent Fingerprints

As a traditional evidence,fingerprint plays a very important role in crime scene investigation and case detection.The definition of public security science and technology on public security research is mainly focused on the technical means of public security work and equipment modernization.With the rapid development of science,information technology,physics and chemistry,forensic science researchers and police staff try to research highintegrated and convenient device,efficient and non-polluting materials,to meet the needs of public security work.This paper study on the application of the macro omnidirectional light source developing latent fingerprints on common object,in the hope of macro omnidirectional light source can meet the requirements of public security technology and equipment modernization.Macro omnidirectional light source has the advantages of high-integrated,high convenience etc.Macro omnidirectional light source has four illumination angle,respectively,directional reflection lighting,dark field lighting,uniform illumination and grazing incident lighting;and seven light stalls,respectively,red light,yellow light,green light,red light,blue light,purple light and white light.In this paper,latent fingerprints on 35 kinds of object with different colors and smoothness has been revealed.The color can be explained as black,white,red,yellow,green and blue.And objects obtain metal paint,plastic,ceramic tile.By changing the illumination angle and the color of the light source,adjusting the camera parameters,the experimental results are obtained,and the optimal extracted conditions for each sample are summarized.Aim to promote the modernization of testing equipment.Research shows that:(1)macro omnidirectional light source has a high effect on the development of latent fingerprints on matte plastic,paint,metal tile with different colors and smoothness;(2)fingerprints on the object of deep color appear better than light color objects;(3)when the test background is deep color,there is a better appearance using the complementary color source,which lines and background has a maximum brightness contrast;(4)when the test background is light color,brightness contrast has not been improved using the complementary color source,so the white color will be the best choice;(5)macro omnidirectional light source has a wide application prospect in the practice of public work.